Show/Hide Menu
Hide/Show Apps
anonymousUser
Logout
Türkçe
Türkçe
Search
Search
Login
Login
OpenMETU
OpenMETU
About
About
Open Science Policy
Open Science Policy
Communities & Collections
Communities & Collections
Help
Help
Frequently Asked Questions
Frequently Asked Questions
Videos
Videos
Thesis submission
Thesis submission
Publication submission with DOI
Publication submission with DOI
Publication submission
Publication submission
Contact us
Contact us
Optimizing OLED efficacy of 2,7-diconjugated 9,9-dialkylfluorenes by variation of periphery substitution and conjugation length
Date
2007-01-05
Author
RATHNAYAKE, Hemali P.
Çırpan, Ali
DELEN, Zeynep
LAHTI, Paul M.
KARASZ, Frank E.
Metadata
Show full item record
This work is licensed under a
Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License
.
Item Usage Stats
8
views
0
downloads
Cite This
The photoluminescence (PL) and electroluminescence (EL) of four 2,7-bis(phenylethenyl)fluorenes (OFPVs) and two 2,7-diphenylfluorenes (OFPhs) are compared to evaluate effects of nonconjugating peripheral substitution and conjugation length on their EL emissions. The OFPVs exhibit very similar PL spectra with 460-480 nm emission maxima but show large variation in the organic light-emitting diode (OLED) efficacy: from a material that does not give persistent emission in test OLEDs (9,9-diheptyl substitution on the fluorene ring) to materials with luminance efficiencies of 0.5 cd A(-1) and greater (9,9-diethyl substitution on the fluorene ring, methoxy and methoxy/heptyloxy substituents on the phenylethenyl rings). The best OFPV in an ITO/PEDOT-PSS/(emitter)/Ca-Al (ITO: indiurn tin oxide; PEDOT: poly(ethylenedioxythiophene); PSS: poly(styrene sulfonate)) OLED configuration has 9,9-diethyl substitution and terminal heptyloxy substitution (maximum luminance of 1500 cd m(-2) at 12 V). Unlike the OFPVs, the neat OFPhs show not only EL at the desired blue output of ca. 400-410 nm emission maxima but also an undesired green emission component at 500-550 nm. Blending the OFPhs with poly(methyl methacrylate) eliminates the long-wavelength component when the emitter load is 10-25 %, but the OFPh luminance efficiencies, turn-on voltages, and maximum luminance tend to be poorer than those of the OFPVs. The deficiencies of the OFPhs appear to be attributable to thermal degradation and oxidative reactivity, although solid-state annealing and a nonoptimal bandgap match to the OLED device configuration may also contribute.
Subject Keywords
Polyfluorene
,
Electroluminescence
,
Emission
,
Polymers
URI
https://hdl.handle.net/11511/39588
Journal
Advanced Functional Materials
DOI
https://doi.org/10.1002/adfm.200600089
Collections
Department of Chemistry, Article
Citation Formats
IEEE
ACM
APA
CHICAGO
MLA
BibTeX
H. P. RATHNAYAKE, A. Çırpan, Z. DELEN, P. M. LAHTI, and F. E. KARASZ, “Optimizing OLED efficacy of 2,7-diconjugated 9,9-dialkylfluorenes by variation of periphery substitution and conjugation length,”
Advanced Functional Materials
, vol. 17, no. 1, pp. 115–122, 2007, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/39588.